Limits of flame propagation in a narrow channel with gas filtration

A model of gas-flame propagation in a narrow gap between two plates is proposed. Apart from the conventional regime, this model describes the regime of low velocities. A typical feature of the low-velocity regime is the fact that the flame propagates together with the heat wave in the plates generated by the flame. It is shown that the limits of flame propagation in the low-velocity regime are wider than the limits in the classical theory. Dependences of the flame-propagation velocity and the critical Peclet number on the fresh-gas velocity are obtained. For Peclet numbers lower than the critical value defined by the classical theory, the flame may exist only within a certain range of velocities of the fresh mixture counterflow. A possible reason for the existence of the upper and lower limits of flame propagation relative to the flow velocity of the fresh mixture is discussed.